Black locust, sometimes called yellow locust, grows naturally on a wide range of sites but does best on rich moist limestone soils. It has escaped cultivation and become naturalized throughout eastern North America and parts of the West. Black locust is not a commercial timber species but is useful for many other purposes. Because it is a nitrogen fixer and has rapid juvenile growth, it is widely planted as an ornamental, for shelterbelts, and for land reclamation. It is suitable for fuelwood and pulp and provides cover for wildlife, browse for deer, and cavities for birds.
Black locust has a disjunct original range, the extent of which is not accurately known. The eastern section is centered in the Appalachian Mountains and ranges from central Pennsylvania and southern Ohio, south to northeastern Alabama, northern Georgia, and northwestern South Carolina. The western section includes the Ozark Plateau of southern Missouri, northern Arkansas, and northeastern Oklahoma, and the Ouachita Mountains of central Arkansas and southeastern Oklahoma. Outlying populations appear in southern Indiana and Illinois, Kentucky, Alabama, and Georgia. Black locust has been planted widely and has become naturalized throughout the United States, southern Canada, and parts of Europe and Asia. 
'Twisty Baby' is a horticultural selection, propagated by grafting, with contorted branches and leaves. What makes the tree especially appealling is the tightly growing leaf clusters that hang down, very much like wisteria blooms. Because black locusts produce new terminal growth all summer long, until leaf fall in autumn, the growing tips are always a fresh apple green color; the leaflets curl up, showing a greyish underside, and the mature leaves a deep, bluish green. The lovely multi-tone effect thus created lasts the entire summer. In winter, the twisted branches have great character as well.
The leading branches of this fast grower (45 cm per year, though some of the growth is downward) can be trained easily by the artistic gardener to a shape that will emphasize their contorted nature, especially when grown as a multi-stemmed specimen. It can reach a height exceeding 3 m, spreading almost as much. Black locusts bloom on mature trees, but 'Twisty Baby' does not bloom reliably. When it does, it produces hanging clusters of white, pea-like blooms with a sweet fragrance; understated, yet spectacular. |